Microbial engineering has long promised the ability to produce a wide array of ingredients, but the commercial viability of these processes has often been a stumbling block. Berkeley-based startup Pow.bio believes that a shift from traditional batch processing to continuous fermentation could be the game-changer the industry needs. At the recent SynBioBeta conference in San Jose, AgFunderNews caught up with Pow.bio’s cofounder and CEO Shannon Hall to delve into this transformative approach.
### Batch vs. Continuous Processing
In the conventional batch precision fermentation process, microbes grow until they reach a critical mass in a fermentation tank. At this point, a change in the media triggers them to produce the target molecule. Once the batch is complete, the ingredient is extracted, and the tank must be cleaned before the process can start anew. This repetitive cycle is not only slow but also resource-intensive, requiring frequent sterilization and setup.
Pow.bio, however, proposes a continuous fermentation process that maintains microbes in a highly productive state for extended periods. Hall asserts that this method can significantly reduce capital expenditure (capex) and increase biomanufacturing capacity by orders of magnitude. By combining continuous fermentation with advanced control methodologies, Pow.bio aims to revolutionize the industry.
### Decoupling Growth and Production
The cornerstone of Pow.bio’s platform is the decoupling of microbial growth and production phases. This separation addresses two significant issues: contamination and genetic drift. “We’ve broken fermentation into unit operations so that we can focus on the performance parameters in each step,” explains Hall. “We focus on growth, then on production, and then on product recovery, so we can have a true conveyor belt of cells in, product out.”
The process involves a small bioreactor dedicated to microbial growth and a larger one focused on production, with a seamless connection between the two. Advanced software and hardware manage the rate of flow, ensuring that cells are continuously recycled, products are recovered, and biomass is efficiently managed. This system is driven by autonomous software, minimizing human intervention and the risks associated with it.
### The Business Model
Pow.bio aims to license and support its technology across various environments. The startup recently raised $9.5 million in a Series A round led by Re:Food and Thia Ventures, bringing its total funding to $13.5 million. “We do services for proof of concept, and we make small amounts of material from grams to hundreds of kilos,” says Hall. From there, companies can decide whether to own or rent the technology based on techno-economic analyses.
### The Stacked Risk Problem
Given the evident benefits of continuous fermentation, why hasn’t it become the industry standard? Hall points to the “stacked risk problem” in biomanufacturing. “People have plenty of risk already, and the infrastructure is built for fed-batch approaches,” she notes. Many startups prefer to stick with incumbent processes because their resources are focused on product design and development.
However, Hall emphasizes the clear advantages of continuous fermentation. “Fundamentally, you can build a smaller facility to generate the same amount of output. So you’re clearly going to have a better return on invested capital and a faster internal return rate.” Modeling continuous systems using Pow.bio technology for new sites shows cost reductions of 30% to 70%.
Despite these benefits, the question of who will bear the initial capex remains. “Nobody wants to pay for the capex to build infrastructure. Everybody’s looking around the table wondering who else could pay? Maybe this is a government initiative?” Hall suggests that a collaborative approach involving multiple stakeholders could be the solution.
The implications of Pow.bio’s continuous fermentation technology are profound. By reducing costs and increasing productivity, it has the potential to make microbial engineering commercially viable on a broader scale. As the industry grapples with the challenges of scaling up, innovations like these could pave the way for more sustainable and efficient biomanufacturing practices.